U.S. patent application number 14/899540 was filed with the patent office on 2016-05-26 for agglomerated precursor for manufacturing light absorption layer of solar cells and method of manufacturing the same.
The applicant listed for this patent is LG CHEM, LTD.. Invention is credited to Seokhee YOON, Seokhyun YOON, Taehun YOON.
Application Number | 20160149059 14/899540 |
Document ID | / |
Family ID | 52432101 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160149059 |
Kind Code |
A1 |
YOON; Seokhee ; et
al. |
May 26, 2016 |
AGGLOMERATED PRECURSOR FOR MANUFACTURING LIGHT ABSORPTION LAYER OF
SOLAR CELLS AND METHOD OF MANUFACTURING THE SAME
Abstract
Disclosed are an aggregated precursor for manufacturing a light
absorption layer of solar cells comprising a first phase comprising
a copper (Cu)-containing chalcogenide and a second phase comprising
an indium (In) and/or gallium (Ga)-containing chalcogenide wherein
30% or more aggregated precursors based on the total amount of
precursors are divided into particle aggregates comprising first
phases and/or second phases, or independent particles having first
phases or second phases, in an ink solvent for manufacturing the
light absorption layer, and a method of manufacturing the same.
Inventors: |
YOON; Seokhee; (Daejeon,
KR) ; YOON; Seokhyun; (Daejeon, KR) ; YOON;
Taehun; (Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG CHEM, LTD. |
Seoul |
|
KR |
|
|
Family ID: |
52432101 |
Appl. No.: |
14/899540 |
Filed: |
August 1, 2014 |
PCT Filed: |
August 1, 2014 |
PCT NO: |
PCT/KR2014/007092 |
371 Date: |
December 17, 2015 |
Current U.S.
Class: |
252/519.4 |
Current CPC
Class: |
C09D 5/32 20130101; H01L
21/02601 20130101; Y02E 10/541 20130101; H01L 31/0322 20130101;
H01L 31/03923 20130101; H01L 21/02628 20130101; H01L 21/02568
20130101; C09D 11/52 20130101 |
International
Class: |
H01L 31/032 20060101
H01L031/032; C09D 5/32 20060101 C09D005/32; C09D 11/52 20060101
C09D011/52 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2013 |
KR |
10-2013-0091791 |
Claims
1. An aggregated precursor for manufacturing a light absorption
layer of solar cells comprising a first phase comprising a copper
(Cu)-containing chalcogenide and a second phase comprising an
indium (In) and/or gallium (Ga)-containing chalcogenide wherein 30%
or more aggregated precursors based on a total weight of precursors
are divided into particle aggregates comprising first phases and/or
second phases, or independent particles having first phases or
second phases.
2. The aggregated precursor according to claim 1, wherein the
aggregated precursor has a diameter of 10 nanometers to 500
nanometers.
3. The aggregated precursor according to claim 1, wherein the
particle aggregate has a diameter of 2 nanometers to 200
nanometers.
4. The aggregated precursor according to claim 1, wherein the
independent particles have diameters of 1 nanometer to 100
nanometers.
5. The aggregated precursor according to claim 1, wherein the
copper (Cu)-containing chalcogenide is at least one selected from
the group consisting of Cu.sub.yS wherein 0.5.ltoreq.y.ltoreq.2.0
and Cu.sub.ySe wherein 0.5.ltoreq.y.ltoreq.2.0.
6. The aggregated precursor according to claim 1, wherein the
indium (In) and/or gallium (Ga)-containing chalcogenide is at least
one selected from the group consisting of
(In.sub.x(Ga).sub.1-x).sub.mSe.sub.n wherein 0.ltoreq.x.ltoreq.1
and 0.5.ltoreq.n/m.ltoreq.2.5, and
(In.sub.x(Ga).sub.1-x).sub.mS.sub.n wherein 0.ltoreq.x.ltoreq.1 and
0.5.ltoreq.n/m.ltoreq.2.5.
7. The aggregated precursor according to claim 1, wherein
composition ratios of chalcogenide elements present in the
aggregated precursor are 0.5 mol to 3 mol based on 1 mol of a
mixture comprising copper (Cu), indium (In) and gallium (Ga).
8. The aggregated precursor according to claim 1, wherein a
composition ratio of the copper (Cu) present in the aggregated
precursor is 0.7 to 1.2 mol based on 1 mol of a mixture of In and
Ga.
9. A method of manufacturing the aggregated precursor for
manufacturing the light absorption layer according to claim 1, the
method comprising: preparing a first solution comprising a reducing
agent; preparing a second solution comprising a sulfur (S) and/or
selenium (Se) compound, a third solution comprising indium (In)
salt or indium (In) salt and gallium (Ga) salt and a fourth
solution comprising a copper (Cu) salt; mixing the first solution
and second solution to manufacture a mixture; mixing and reacting
the third solution with the mixture of the mixing to synthesize
indium (In) and/or gallium (Ga)-containing chalcogenide particles;
and synthesizing the aggregated precursor for manufacturing a light
absorption layer by mixing the fourth solution with the solution
comprising the indium (In) and/or gallium (Ga)-containing
chalcogenide particles of the mixing and reacting to synthesize a
first phase comprising a copper (Cu)-containing chalcogenide and a
second phase comprising an indium (In) and/or gallium
(Ga)-containing chalcogenide.
10. The method according to claim 9, wherein, when the fourth
solution is mixed with the indium (In) and/or gallium
(Ga)-containing chalcogenide particles of the synthesizing, an
additive is further added.
11. The method according to claim 9, wherein, before the
synthesizing, a fifth solution comprising a reducing agent and a
sixth solution comprising a sulfur (S) and/or selenium (Se)
compound are mixed to manufacture a mixture and then the mixture is
mixed with the solution comprising the indium (In) and/or gallium
(Ga)-containing chalcogenide particles of the synthesizing and the
fourth solution, regardless of the preparing to the mixing.
12. The method according to claim 11, wherein, when the mixture of
the fifth solution and the sixth solution, the solution comprising
indium (In) and/or gallium (Ga)-containing chalcogenide particles
and the fourth solution are mixed, an additive is further
added.
13. The method according to claim, wherein the reducing agent is an
organic reducing agent and/or inorganic reducing agent.
14. (canceled)
15. A method of manufacturing the aggregated precursor for
manufacturing the light absorption layer according to claim 1, the
method comprising: preparing a first solution comprising a sulfur
(S) and/or selenium (Se) compound, a second solution comprising an
indium (In) salt or indium (In) salt and gallium (Ga) salt, and a
third solution comprising a copper (Cu) salt; mixing and reacting
the first solution and the second solution to synthesize indium
(In) and/or gallium (Ga)-containing chalcogenide particles; and
mixing the third solution with the solution comprising the indium
(In) and/or gallium (Ga)-containing chalcogenide particles of the
mixing and reacting to synthesize and purify an aggregated
precursor for manufacturing a light absorption layer comprising the
first phase comprising the copper (Cu)-containing chalcogenide and
the second phase comprising the indium (In) and/or gallium
(Ga)-containing chalcogenide
16. The method according to claim 15, wherein, when the indium (In)
and/or gallium (Ga)-containing chalcogenide particles of the mixing
are mixed with the third solution, an additive is further
added.
17. The method according to claim 15, wherein, when the indium (In)
and/or gallium (Ga)-containing chalcogenide particles of the mixing
are mixed with the third solution, a fourth solution comprising a
sulfur (S) and/or selenium (Se) compound is mixed together.
18. The method according to claim 17, wherein, when the solution
comprising the indium (In) and/or gallium (Ga)-containing
chalcogenide particles, the third solution and the fourth solution
are mixed, an additive is further added.
19. The method according to claim 9, wherein the sulfur (S)
compound is at least one selected from the group consisting of
sulfur (S) powder, H.sub.2S, Na.sub.2S, K.sub.2S, CaS,
(CH.sub.3).sub.2S, H.sub.2SO.sub.4 and hydrates thereof, thiourea,
and thioacetamide.
20. The method according to claim 9, wherein the selenium (Se)
compound is at least one selected from the group consisting of Se
powder, H.sub.2Se, Na.sub.2Se, K.sub.2Se, CaSe, (CH.sub.3).sub.2Se,
SeO2, SeCl.sub.4, H.sub.2SeO.sub.3, H.sub.2SeO.sub.4 and hydrates
thereof, selenourea, and selenous acid.
21-23. (canceled)
24. An ink composition wherein the aggregated precursor for
manufacturing the light absorption layer according to claim 1
dispersed in a solvent exists as a particle aggregate comprising a
first phase comprising a copper (Cu)-containing chalcogenide and/or
a second phase comprising an indium (In) and/or gallium
(Ga)-containing chalcogenide or independent particles having a
first phase or a second phase.
25-31. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present invention is a U.S. National Stage of
PCT/KR2014/007092, filed Aug. 1, 2014, which claims the priority of
Korean patent application No. 10-2013-0091791, filed Aug. 1, 2013,
which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to an aggregated precursor for
manufacturing a light absorption layer of solar cells and a method
of manufacturing the same.
BACKGROUND ART
[0003] Recently, people are more concerned about environmental
problems and depletion of natural resources and, as such, interest
in solar cells as an alternative energy source which does not cause
environmental pollution is growing. Solar cells are classified into
silicon solar cells, thin film-type compound solar cells,
layered-type solar cells and the like. Among these solar cells,
silicon semiconductor solar cells have been studied the most
widely.
[0004] Among these solar cells, recently, thin film type compound
solar cells are actively studied and developed.
[0005] Among thin film type compound semiconductors,
Cu(In.sub.1-xGa.sub.x)(Se.sub.yS.sub.1-y) (CI(G)S), which is a
Group I-III-VI compound included in ternary compounds, has a direct
transition type energy band gap of 1 eV or more and high light
absorption coefficient. In addition, the
Cu(In.sub.1-xGa.sub.x)(Se.sub.yS.sub.1-y) (CI(G)S) is an
electro-optically stable. Thus, the
Cu(In.sub.1-xGa.sub.x)(Se.sub.yS.sub.1-y) (CI(G)S) is an ideal
material as a light absorption layer of solar cells.
[0006] CI(G)S based solar cells are made by forming a light
absorption layer having a thickness of several microns. As methods
of manufacturing the light absorption layer, a vacuum deposition
method which does not require a precursor, a sputtering method
which forms a CI(G)S thin film through heat treatment after forming
a thin film with a precursor and an electrodeposition method were
introduced. Recently, an ink coating method was introduced.
According to the ink coating method, under non-vacuum, a precursor
material is coated and then the coated material is heat-treated.
Among these light absorption layer manufacturing methods, studies
into the ink coating method are actively conducted since, by using
the ink coating method, process costs may be reduced and a large
area may be uniformly manufactured. Precursors used in the ink
coating method may be various compounds or metals such as metal
chalcogenide compounds, bimetallic metal particles, metal salts,
metal oxides or the like.
[0007] In particular, when a metal chalcogenide compound is used as
a precursor, a mixed Cu--Se and In--Se compound or synthesized
CuInSe.sub.2 single-phase particles are used. When the mixed
particles are used, a coating layer having a partially non-uniform
composition may be formed. When the CuInSe.sub.2 single-phase
particles are used, long reaction time for particle growth is
required.
[0008] Therefore, there is a high need to develop a technology for
a precursor which may form a highly efficient light absorption
layer having an entirely more uniform composition, being stable
against oxidation and having increased film density.
DISCLOSURE
Technical Problem
[0009] Therefore, the present invention has been made to solve the
above and other technical problems that have yet to be
resolved.
[0010] As a result of a variety of intensive studies and various
experiments, the inventors of the present invention developed an
aggregated precursor including a first phase including a copper
(Cu)-containing chalcogenide and a second phase including an indium
(In) and/or gallium (Ga)-containing chalcogenide such that all
constituting elements forming a light absorption layer are
included, and confirmed that, when a thin film is manufactured
using the aggregated precursor, the thin film has an entirely
uniform composition and is stable against oxidation and the amount
of a Group VI element included in the thin film is increased due to
S or Se included in the precursor, thus completing the present
invention.
Technical Solution
[0011] In accordance with one aspect of the present invention,
provided is a precursor for manufacturing a light absorption layer
including a first phase including a copper (Cu)-containing
chalcogenide and a second phase including an indium (In) and/or
gallium (Ga)-containing chalcogenide as an aggregated precursor
wherein 30% or more aggregated precursors based on the total weight
of the precursors are divided into particle aggregates including
first phases and/or second phases, or independent particles having
first phases or second phases in an ink solvent for manufacturing
the light absorption layer in an ink solvent for manufacturing the
light absorption layer.
[0012] The term "aggregated precursor", as used in the present
invention means a precursor type in which independent particles are
uniformly aggregated such that two or more phases are included. The
term "particle aggregate" means a type of independent particle
aggregated to a small amount in a smaller range than the aggregated
precursor as a portion separated from the aggregated precursor. In
addition, the term "independent particle" means a single
particle.
[0013] Therefore, the aggregated precursor, particle aggregate and
independent particles have different concepts in the present
invention.
[0014] In a specific embodiment, the diameters of the independent
particles on which all constitutions are based may be 1 nanometer
to 100 nanometers, particularly 5 nanometers to 100 nanometers.
[0015] In addition, the diameter of the particle aggregate in which
independent particles is aggregated in a small amount and which
broadly means all type of two or more particles aggregated in a
small amount may be 2 nanometers to 200 nanometers in the broadest
range. The diameter of the aggregated precursor from which the
particle aggregate originates may be 10 nanometers to 500
nanometers, particularly 15 nanometers to 300 nanometers in a
broader range than the particle aggregate.
[0016] Meanwhile, the "chalcogenide" of the present invention means
a Group VI element, for example, a material including sulfur (S)
and/or selenium (Se). In a specific embodiment, the copper
(Cu)-containing chalcogenide may be at least one selected from the
group consisting of Cu.sub.yS (0.5.ltoreq.y.ltoreq.2.0) and
Cu.sub.ySe (0.5.ltoreq.y.ltoreq.2.0), and the indium (In) and/or
gallium (Ga) chalcogenide may be at least one selected from the
group consisting of (In.sub.x(Ga).sub.1-x).sub.mSe.sub.n
(0.ltoreq.x.ltoreq.1 and 0.5.ltoreq.n/m.ltoreq.2.5) and
(In.sub.x(Ga).sub.1-x).sub.mS.sub.n (0.ltoreq.x.ltoreq.1 and
0.5.ltoreq.n/m.ltoreq.2.5).
[0017] As described above, when the aggregated precursor includes
two or more phase types, the composition ratio of the chalcogenide
element may be 0.5 mol to 3 mol based on 1 mol of a mixture of
copper (Cu), indium (In) and gallium (Ga), with respect to the
total amount of the aggregated precursor.
[0018] Outside this range, when the composition ratio of the
chalcogenide element is less than 0.5 mol, the Group VI element is
not sufficiently provided and, as such, a film in which the Group
VI element is partially deficient may be formed. On the contrary,
when the composition ratio of the chalcogenide element exceeds 3
mol, the Group VI element is non-uniformly distributed in a thin
film and, as such, a film may non-uniformly grow.
[0019] In addition, a composition ratio of copper (Cu) may be 0.7
to 1.2 based on 1 mol of a mixture of In and Ga with respect to the
total amount of the aggregated precursor.
[0020] Outside this range, when the composition ratio of copper
(Cu) exceeds 1.2 mol, the first phase including the copper
(Cu)-containing chalcogenide exists in a relatively large amount
and, as such, particles may easily grow but Cu impurities may be
generated. On the contrary, when the composition ratio of copper
(Cu) is less than 0.7 mol, the first phase including the copper
(Cu)-containing chalcogenide is deficient and thereby the diameters
of the particles are small and formation of a p-type CI(G)S thin
film is not easy, and, accordingly, performances are poor.
[0021] As described above, in the ink solvent for manufacturing the
light absorption layer, a certain amount or more of the aggregated
precursor according the present invention is divided into the
particle aggregate including the first phase and/or second phase,
or independent particles having a first phase or a second
phase.
[0022] As described above, when some particle aggregates separated
from the aggregated precursor exist in a uniformly distributed
state, the separated particle aggregates may be more uniformly
distributed than the aggregated precursor. Therefore, when an ink
is coated to manufacture a thin film, coating properties may be
improved. In addition, when compared with an ink manufactured using
nanoparticles including a first phase or nanoparticles including a
second phase separately dispersed in a solvent, an ink manufactured
using the aggregated precursor has a more uniform composition.
Further, when compared with an ink manufactured using single-phase
particles including all elements forming a light absorption layer,
by using an ink manufactured using the aggregated precursors, a
CI(G)S thin film may be smoothly grown.
[0023] The above ink solvent for manufacturing the light absorption
layer will be separately described later.
[0024] Methods of manufacturing the aggregated precursor for
manufacturing the light absorption layer may be broadly divided
into two methods.
[0025] As a first example, a method of manufacturing the aggregated
precursor including sulfur (S) and/or selenium (Se) includes:
[0026] (i) preparing a first solution including a reducing
agent;
[0027] (ii) preparing a second solution including a sulfur (S)
and/or selenium (Se) compound, a third solution including indium
(In) salt and/or gallium (Ga) salt and a fourth solution including
a copper (Cu) salt;
[0028] (iii) mixing the first solution and second solution to
manufacture a mixture;
[0029] (iv) mixing and reacting the third solution with the mixture
of the mixing to synthesize indium (In) and/or gallium
(Ga)-containing chalcogenide particles; and
[0030] (v) mixing the fourth solution with the solution including
the indium (In) and/or gallium (Ga)-containing chalcogenide
particles of the mixing and reacting to synthesize a first phase
including a copper (Cu)-containing chalcogenide and a second phase
including an indium (In) and/or gallium (Ga)-containing
chalcogenide to synthesize the aggregated precursor for
manufacturing a light absorption layer.
[0031] In addition, as a method of manufacturing an aggregated
precursor including sulfur(S) and/or selenium (Se), to obtain a
more sufficient Group VI element, a mixture is manufactured by
mixing a fifth solution including a reducing agent and a sixth
solution including a sulfur(S) and/or selenium (Se) compound,
regardless of step (i) to step (iii), before step (v), and the
mixture is mixed with the solution including indium (In) and/or
gallium (Ga)-containing chalcogenide particles and the fourth
solution of step (v) to manufacture an aggregated precursor.
[0032] Regardless of manufacturing methods, the method of
manufacturing the aggregated precursor according to the present
invention is carried out through sequential processes in one
reactor and, as such, the aggregated precursor has unique
characteristics described above and may have a more uniform
composition when compared with a precursor manufactured by
separately synthesizing the nanoparticles including the first phase
and the nanoparticles including the second phase, and then mixing
the nanoparticles including the first phase or the nanoparticles
including the second phase. As well as, when compared with use of
CuInS(Se).sub.2 single-phase particles, time required for growth
and reaction of particles times may be shortened.
[0033] Especially, when the mixture was mixed with the third
solution in step (iv) and the solution including the indium (In)
and/or gallium (Ga)-containing chalcogenide particles of step (iv)
and the fourth solution are mixed, by stirring a solution while
slowly adding the third solution and fourth solution dropwise, an
aggregated precursor having a uniform composition and size may be
obtained.
[0034] As a specific embodiment, in both cases, to improve
dispersibility of an aggregated precursor and to obtain uniform
composition distribution, when the fourth solution is mixed with
the solution including the indium (In) and/or gallium
(Ga)-containing chalcogenide particles of step (v), or a mixture of
the fifth solution and the sixth solution, the solution including
the indium (In) and/or gallium (Ga)-containing chalcogenide
particles, and the fourth solution are mixed, an additive may be
further added.
[0035] The additive is not specifically limited so long as the
additive may used as a dispersing agent and, for example, may be at
least one selected from the group consisting of
polyvinylpyrrolidone (PVP), polyvinyl alcohol, and ethyl
cellulose.
[0036] In a specific embodiment, the reducing agent included in the
first solution may be an organic reducing agent and/or an inorganic
reducing agent and particularly one selected from the group
consisting of LiBH.sub.4, NaBH.sub.4, KBH.sub.4,
Ca(BH.sub.4).sub.2, Mg(BH.sub.4).sub.2, LiB(Et).sub.3H,
NaBH.sub.3(CN), NaBH(OAc).sub.3, hydrazine, ascorbic acid and
triethanolamine.
[0037] Accordingly, the method of manufacturing the aggregated
precursor is performed by a solution process instead of the prior
vacuum process and, as such, process costs may be reduced.
[0038] In a specific embodiment, solvents for the first solution to
sixth solution each independently may be at least one selected from
the group consisting of water, alcohols, acetic acids, diethylene
glycol (DEG), oleylamine, ethylene glycol, triethylene glycol,
dimethyl sulfoxide, dimethyl formamide, and N-methyl-2-pyrrolidone
(NMP). The alcohol solvents may be methanol, ethanol, propanol,
butanol, pentanol, hexanol, heptanol and octanol having 1 to 8
carbons.
[0039] In a specific embodiment, as the Group VI source included in
the second solution, the sulfur (S) compound may be at least one
selected from the group consisting of, for example, sulfur (S)
powder, H.sub.2S, Na.sub.2S, K.sub.2S, CaS, (CH.sub.3).sub.2S,
H.sub.2SO.sub.4, and hydrates thereof, thiourea, and thioacetamide,
and the selenium (Se) compound may be at least one selected from
the group consisting of, for example, Se powder, H.sub.2Se,
Na.sub.2Se, K.sub.2Se, CaSe, (CH.sub.3).sub.2Se, SeO2, SeCl.sub.4,
H.sub.2SeO.sub.3, H.sub.2SeO.sub.4 and hydrates thereof,
selenourea, and selenous acid.
[0040] In a specific embodiment, the salts included in the third
solution and fourth solution may be at least one selected from the
group consisting of chlorides, bromides, iodides, nitrates,
nitrites, sulfates, acetates, sulfites, acetylacetonate and
hydroxides.
[0041] Meanwhile, as another example, a method of manufacturing the
aggregated precursor including sulfur (S) and/or selenium (Se)
includes:
[0042] (i) preparing a first solution including a sulfur (S) and/or
selenium (Se) compound, a second solution including an indium (In)
salt or indium (In) salt and gallium (Ga) salt, and a third
solution including a copper (Cu) salt;
[0043] (ii) mixing and reacting the first solution and second
solution to synthesize indium (In) and/or gallium (Ga)-containing
chalcogenide particles; and
[0044] (iii) mixing the third solution with the solution including
the indium (In) and/or gallium (Ga)-containing chalcogenide
particles of step (ii) to synthesize and purify an aggregated
precursor for manufacturing a light absorption layer including the
first phase including the copper (Cu)-containing chalcogenide and
the second phase including the indium (In) and/or gallium
(Ga)-containing chalcogenide.
[0045] Accordingly, the method of manufacturing the aggregated
precursor is carried out by a solution process instead of a vacuum
process and, as such, process costs may be reduced.
[0046] The second method of manufacturing the aggregated precursor
is similar to the first method of manufacturing the aggregated
precursor in that, to obtain a sufficient amount of the Group VI
element, when the third solution is mixed with the solution
including the indium (In) and/or gallium (Ga)-containing
chalcogenide particles of step (iii), an aggregated precursor may
be manufactured by mixing the fourth solution including the sulfur
(S) and/or selenium (Se) compound besides the first solution of
step (i).
[0047] Regardless of manufacturing methods, the method of
manufacturing the aggregated precursor according to the present
invention is carried out through sequential processes in one
reactor and, as such, the aggregated precursor has unique
characteristics described above and may have a more uniform
composition when compared with a precursor manufactured by
separately synthesizing the nanoparticles including the first phase
and nanoparticles including the second phase, and then mixing the
nanoparticles including the first phase or the nanoparticles
including the second phase. In addition, when compared with use of
CuInS(Se).sub.2 single-phase particles, time required for growth
and reaction of particles times may be shortened
[0048] In addition, when the first solution and second solution are
mixed, and the third solution is mixed with the solution including
the indium (In) and/or gallium (Ga)-containing chalcogenide
particles of step (ii), by stirring a mixture while slowly adding
the second solution and third solution dropwise, an aggregated
precursor having a uniform composition and size may be
obtained.
[0049] As a specific embodiment, in both cases, to improve
dispersibility of an aggregated precursor and to obtain uniform
composition distribution, when the third solution is mixed with the
solution including the indium (In) and/or gallium (Ga)-containing
chalcogenide particles of step (iii), or the solution including the
indium (In) and/or gallium (Ga)-containing chalcogenide particles,
the third solution and the fourth solution are mixed, and an
additive may be further added.
[0050] Here, concrete examples of the additive are the same as
those described above.
[0051] In addition, the other solvent and salt types of the sulfur
(S) compound, selenium (Se) compound and the first solution to
fourth solution are the same as those described above.
[0052] The present invention also provides a method of
manufacturing a thin film using the ink composition.
[0053] A method of manufacturing the thin film according to the
present invention includes:
[0054] (i) dispersing an aggregated precursor for manufacturing a
light absorption layer including a first phase including a copper
(Cu)-containing chalcogenide and a second phase including an indium
(In) and/or gallium (Ga)-containing chalcogenide in a solvent to
manufacture an ink;
[0055] (ii) coating the ink on a base provided with an electrode;
and
[0056] (iii) drying and then heat-treating the ink coated on the
base provided with an electrode.
[0057] As a specific embodiment, the solvent of step (i) is not
particularly limited so long as the solvent is a general organic
solvent and may be one organic solvent selected from among alkanes,
alkenes, alkynes, aromatics, ketones, nitriles, ethers, esters,
organic halides, alcohols, amines, thiols, carboxylic acids,
phosphines, phosphites, phosphates, sulfoxides, and amides or a
mixture of at least one organic solvent selected therefrom.
[0058] In particular, the alcohols may be at least one mixed
solvent selected from among ethanol, 1-propanol, 2-propanol,
1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, heptanol,
octanol, ethylene glycol (EG), diethylene glycol monoethyl ether
(DEGMEE), ethylene glycol monomethyl ether (EGMME), ethylene glycol
monoethyl ether (EGMEE), ethylene glycol dimethyl ether (EGDME),
ethylene glycol diethyl ether (EGDEE), ethylene glycol monopropyl
ether (EGMPE), ethylene glycol monobutyl ether (EGMBE),
2-methyl-1-propanol, cyclopentanol, cyclohexanol, propylene glycol
propyl ether (PGPE), diethylene glycol dimethyl ether (DEGDME),
1,2-propanediol (1,2-PD), 1,3-propanediol (1,3-PD), 1,4-butanediol
(1,4-BD), 1,3-butanediol (1,3-BD), .alpha.-terpineol, diethylene
glycol (DEG), glycerol, 2-(ethylamino)ethanol,
2-(methylamino)ethanol, and 2-amino-2-methyl-1-propanol.
[0059] The amines may be at least one mixed solvent selected from
among triethyl amine, dibutyl amine, dipropyl amine, butylamine,
ethanolamine, diethylenetriamine (DETA), triethylenetetramine
(TETA), triethanolamine, 2-aminoethyl piperazine, 2-hydroxyethyl
piperazine, dibutylamine, and tris(2-aminoethyl)amine.
[0060] The thiols may be at least one mixed solvent selected from
among 1,2-ethanedithiol, pentanethiol, hexanethiol, and
mercaptoethanol.
[0061] The alkanes may be at least one mixed solvent selected from
among hexane, heptane, and octane.
[0062] The aromatics may be at least one mixed solvent selected
from among toluene, xylene, nitrobenzene, and pyridine.
[0063] The organic halides may be at least one mixed solvent
selected from among chloroform, methylene chloride,
tetrachloromethane, dichloroethane, and chlorobenzene.
[0064] The nitriles may be acetonitrile.
[0065] The ketones may be at least one mixed solvent selected from
among acetone, cyclohexanone, cyclopentanone, and acetyl
acetone.
[0066] The ethers may be at least one mixed solvent selected from
among ethyl ether, tetrahydrofuran, and 1,4-dioxane.
[0067] The sulfoxides may be at least one mixed solvent selected
from among dimethyl sulfoxide (DMSO) and sulfolane.
[0068] The amides may be at least one mixed solvent selected from
among dimethyl formamide (DMF) and n-methyl-2-pyrrolidone
(NMP).
[0069] The esters may be at least one mixed solvent selected from
among ethyl lactate, .gamma.-butyrolactone, and ethyl
acetoacetate.
[0070] The carboxylic acids may be at least one mixed solvent
selected from among propionic acid, hexanoic acid,
meso-2,3-dimercaptosuccinic acid, thiolactic acid, and thioglycolic
acid.
[0071] However, the solvents are only given as an example, and
embodiments of the present invention are not limited thereto.
[0072] In some cases, the ink of step (i) may further include an
additive.
[0073] The additive may, for example, be at least one selected from
the group consisting of a dispersant, a surfactant, a polymer, a
binder, a crosslinking agent, an emulsifying agent, an anti-foaming
agent, a drying agent, a filler, a bulking agent, a thickening
agent, a film conditioning agent, an antioxidant, a fluidizer, a
leveling agent, and a corrosion inhibitor. In particular, the
additive may be at least one selected from the group consisting of
polyvinylpyrrolidone (PVP), polyvinyl alcohol, Anti-terra 204,
Anti-terra 205, ethyl cellulose, and DispersBYK110.
[0074] The coating of step (ii) may be any one selected from the
group consisting of wet coating, spray coating, spin-coating,
doctor blade coating, contact printing, top feed reverse printing,
bottom feed reverse printing, nozzle feed reverse printing, gravure
printing, micro gravure printing, reverse micro gravure printing,
roller coating, slot die coating, capillary coating,
inkjet-printing, jet deposition, and spray deposition.
[0075] The heat treatment of step (iii) may be carried out at a
temperature of 400 to 900.degree. C.
[0076] Meanwhile, a selenization process may be included to prepare
the thin film of a solar cell having much higher density. The
selenization process may be carried out through a variety of
methods.
[0077] As a first example, effects obtained from the selenization
process may be achieved by manufacturing an ink by dispersing S
and/or Se in a particle type in a solvent with the aggregated
precursor for manufacturing the light absorption layer in step (i),
and by combining the heat treatment of step (iii)
[0078] As a second example, effects obtained from the selenization
process may be achieved through the heat treatment of step (iii) in
the presence of S or Se
[0079] In particular, S or Se may be present by supplying H.sub.2S
or H.sub.2Se in a gaseous state or supplying Se or S in a gaseous
state through heating.
[0080] As a third example, after step (ii), S or Se may be stacked
on the coated base, followed by performing step (iii). In
particular, the stacking process may be performed by a solution
process or a deposition method.
[0081] The present invention also provides a thin film manufactured
according to the above method.
[0082] The thickness of the thin film may be 0.5 to 5.0 .mu.m, more
particularly 0.5 to 3.0 .mu.m.
[0083] When the thickness of the thin film is less than 0.5 .mu.m,
the density and amount of the light absorption layer are
insufficient and thus desired photoelectric efficiency may not be
obtained. On the other hand, when the thickness of the thin film
exceeds 5.0 .mu.m, movement distances of carriers increases and,
accordingly, there is an increasing probability of recombination,
which results in reduced efficiency.
[0084] Furthermore, the present invention provides a thin film
solar cell manufactured using the thin film.
[0085] A method of manufacturing a thin film solar cell is known in
the art and thus a detailed description thereof will be omitted
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0086] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawing, in which:
[0087] FIG. 1 is a scanning electron microscope (SEM) image of
In.sub.2Se.sub.3--CuSe powder formed according to Example 1;
[0088] FIG. 2 is an X-ray diffraction (XRD) graph of
In.sub.2Se.sub.3--CuSe powder formed according to Example 1;
[0089] FIG. 3 is a scanning electron microscope (SEM) image of
In.sub.2Se.sub.3--CuSe powder formed according to Example 2;
[0090] FIG. 4 is an X-ray diffraction (XRD) graph of
In.sub.2Se.sub.3--CuSe powder formed according to Example 2;
[0091] FIG. 5 is a scanning electron microscope (SEM) image of
In.sub.2Se.sub.3--CuSe powder formed according to Example 3;
[0092] FIG. 6 is an X-ray diffraction (XRD) graph of
In.sub.2Se.sub.3--CuSe powder formed according to Example 3;
[0093] FIG. 7 is a scanning electron microscope (SEM) image of
In.sub.0.7Ga.sub.0.3Se.sub.1.5--CuSe powder formed according to
Example 4;
[0094] FIG. 8 is an X-ray diffraction (XRD) graph of
In.sub.0.7Ga.sub.0.3Se.sub.1.5--CuSe powder formed according to
Example 4;
[0095] FIG. 9 is a scanning electron microscope (SEM) image of
In.sub.2S.sub.3--Cusulfur (S) powder formed according to Example
5;
[0096] FIG. 10 is a scanning electron microscope (SEM) image of
(In,Ga).sub.2Se.sub.3--CuSe powder formed according to Example
6;
[0097] FIG. 11 is an X-ray diffraction (XRD) graph of
(In,Ga).sub.2Se.sub.3--CuSe powder formed according to Example
6;
[0098] FIG. 12 is a scanning electron microscope (SEM) image of
In.sub.2Se.sub.3--CuSe powder formed according to Example 7;
[0099] FIG. 13 is an X-ray diffraction (XRD) graph of
In.sub.2Se.sub.3--CuSe powder formed according to Example 7;
[0100] FIG. 14 is a scanning electron microscope (SEM) image of
CuInSe.sub.2 powder formed according to Comparative Example 1;
[0101] FIG. 15 is an XRD graph of CuInSe.sub.2 powder formed
according to Comparative Example 1;
[0102] FIGS. 16a-16b are SEM images of a thin film manufactured
according to Example 8;
[0103] FIG. 17 is an XRD graph of a thin film manufactured
according to Example 8;
[0104] FIGS. 18a-18b are SEM images of a thin film manufactured
according to Example 9;
[0105] FIG. 19 is an XRD graph of a thin film manufactured
according to Example 9;
[0106] FIGS. 20a-20b are SEM images of a thin film manufactured
according to Example 10;
[0107] FIG. 21 is an XRD graph of a thin film manufactured
according to Example 10;
[0108] FIGS. 22a-22b are SEM images of a thin film manufactured
according to Example 11;
[0109] FIG. 23 is an XRD graph of a thin film manufactured
according to Example 11;
[0110] FIG. 24 is an SEM image of a thin film manufactured
according to Comparative Example 2;
[0111] FIG. 25 is an XRD graph of a thin film manufactured
according to Comparative Example 2; and
[0112] FIG. 26 is a graph showing IV characteristics of a thin film
solar cell manufactured according to Example 15.
BEST MODE
[0113] Now, the present invention will be described in more detail
with reference to the following examples. These examples are
provided only for illustration of the present invention and should
not be construed as limiting the scope and spirit of the present
invention.
EXAMPLE 1
[0114] Synthesis of In.sub.2Se.sub.3--CuSe particles
[0115] Under a nitrogen atmosphere, after mixing 1.974 g of
NaBH.sub.4 in 100 ml of distilled water, 1.974 g of Se powder was
added thereto and then 100 ml of distilled water was further added.
After confirming formation of a colorless and transparent solution,
the solution was further stirred for 15 minutes. Subsequently, a
solution produced by dissolving 2.212 g of InCl.sub.3 in 50 ml
distilled water was added thereto. The resulting mixture was
further stirred for 10 minutes and then 50 ml of distilled water in
which 1.705 g of CuCl.sub.2 was dissolved was slowly added thereto.
The resulting mixture was further stirred for 1 hour and then
centrifuged. As a result, powder having a CuInSe.sub.2.5
composition was obtained in a yield of 99%. The powder was analyzed
using ICP. As a result, it was confirmed that the CuInSe.sub.2.5
composition of the powder has a ratio of Cu:In:Se of
22.18:22.56:55.26 in mol %. As an XRD analysis result of the
particles, CuSe crystalline phases were observed and it was
confirmed that amorphous In.sub.2Se.sub.3 and superior CuSe
crystalline phases were mixed. SEM-EDX and XRD analysis results of
the particles are illustrated in FIGS. 1 and 2.
EXAMPLE 2
[0116] Synthesis of In.sub.2Se.sub.3--CuSe particles
[0117] Under a nitrogen atmosphere, after mixing 1.90 g of
NaBH.sub.4 in 150 ml of distilled water, 3.224 g of
H.sub.2SeO.sub.3 dissolved in 60 ml of distilled water was added
dropwise. After confirming formation of a colorless and transparent
solution, a solution produced by dissolving 2.212 g of InCl.sub.3
in 35 ml of distilled water was added thereto and then stirred for
5 minutes. Subsequently, 40 ml of distilled water in which 1.705 g
of CuCl.sub.2*2H.sub.2O was dissolved was added thereto. The
resulting mixture was further stirred for one day and then
centrifuged. As a result, powder having a CuInSe.sub.2.5
composition was obtained in a yield of 99%. The powder was analyzed
using ICP. As a result, it was confirmed that the CuInSe.sub.2.5
composition of the powder has a ratio of Cu: In: Se of
2.42:22.20:56.38 in mol %. As an XRD analysis result of the
particles, CuSe crystalline phases were observed and it was
confirmed that amorphous In.sub.2Se.sub.3 and superior CuSe
crystalline phases were mixed. SEM-EDX and XRD analysis results of
the particles are illustrated in FIGS. 3 and 4.
EXAMPLE 3
[0118] Synthesis of In.sub.2Se.sub.3--CuSe particles
[0119] Under a nitrogen atmosphere, 1.135 g of NaBH.sub.4 was added
to 50 ml of distilled water and dissolved therein. Subsequently, a
solution produced by dissolving 1.935 g of H.sub.2SeO.sub.3 in 30
ml of distilled water was added thereto. After confirming formation
of a colorless and transparent solution, a solution produced by
dissolving 2.212 g of InCl.sub.3 in 50 ml of distilled water was
added thereto and then was further stirred for 3.5 hours, resulting
in In.sub.2Se.sub.3 particle formation. Under a nitrogen
atmosphere, after dissolving 0.757 g of NaBH.sub.4 in 50 ml of
distilled water in another flask and then a solution produced by
dissolving 1.290 g of H.sub.2SeO.sub.3 in 20 ml of distilled water
was added thereto. The resulting mixture was stirred until a clear
solution was observed. To this clear solution, the previously
manufactured In.sub.2Se.sub.3 solution was added. Subsequently, a
solution produced by dissolving 1.705 g of CuCl.sub.2*2H.sub.2O in
50 ml of distilled water was added thereto and then was stirred for
1 day. The resulting solution was purified through centrifugation
and then vacuum-dried, resulting in particles having a
CuInSe.sub.2.5 composition. The particles were analyzed using ICP.
As a result, it was confirmed that the CuInSe.sub.2.5 composition
particles have a composition as follows: Cu:In:Se of
21.80:21.89:56.31 in mol %. In addition, as an XRD analysis result,
the particles were observed as having a CuSe crystalline phase and
as being in a mixed state of amorphous In.sub.2Se.sub.3 and CuSe
having superior crystallinity. SEM-EDX and XRD results of the
particles are illustrated in FIGS. 5 and 6.
EXAMPLE 4
[0120] Synthesis of In.sub.0.7Ga.sub.0.3Se.sub.1.5--CuSe
particles
[0121] Under a nitrogen atmosphere, 2.270 g of NaBH.sub.4 was added
to 100 ml of distilled water and dissolved therein. Subsequently, a
solution produced by dissolving 3.869 g of H.sub.2SeO.sub.3 in 60
ml of distilled water was added thereto. After confirming formation
of a colorless and transparent solution, a solution produced by
dissolving 3.097 g of InCl.sub.3 and 2.703 g of GaI.sub.3 in 100 ml
of distilled water was added thereto and then was further stirred
for 1 day, resulting in In.sub.0.7Ga.sub.0.3Se.sub.1.5 particle
formation. Under a nitrogen atmosphere, after dissolving 1.665 g of
NaBH.sub.4 in 100 ml of distilled water in another flask and then a
solution produced by dissolving 2.837 g of H.sub.2SeO.sub.3 in 40
ml of distilled water was added thereto. The resulting mixture was
stirred until a clear solution was observed. To this clear
solution, the previously manufactured
In.sub.0.7Ga.sub.0.3Se.sub.1.5 solution was added. Subsequently, a
solution produced by dissolving 3.410 g of CuCl.sub.2*2H.sub.2O in
100 ml of distilled water was added thereto and then was stirred
for five hours. The resulting solution was purified through
centrifugation and then vacuum-dried, resulting in particles having
a CuIn.sub.0.7Ga.sub.0.3Se.sub.2.5 composition. The particles were
analyzed using ICP. As a result, it was confirmed that the
CuIn.sub.0.7Ga.sub.0.3Se.sub.2.5 composition particles have a
composition as follows: Cu:In:Ga:Se:Na:B of
20.07:14.19:5.88:55.885:3.73:0.26 in mol %. In addition, as an XRD
analysis result, the particles were observed as having a CuSe
crystalline phase and as being in a mix state of amorphous
(In,Ga).sub.2Se.sub.3 and CuSe having superior crystallinity.
SEM-EDX and XRD results of the particles are illustrated in FIGS. 7
and 8.
EXAMPLE 5
[0122] Synthesis of In.sub.2S.sub.3--CuS particles
[0123] Under a nitrogen atmosphere, 3.603 g of Na.sub.2S*9H.sub.2O
was dissolved in 60 ml of distilled water and then a solution
produced by dissolving 2.212 g of InCl.sub.3 in 40 ml of distilled
water was added thereto. The resulting solution was further stirred
for one hour. To the solution, a solution produced by dissolving
2.402 g of Na.sub.2S*9H.sub.2O in 50 ml of distilled water was
added and then stirred for ten minutes. Subsequently, a solution
produced by dissolving 1.705 g of CuCl.sub.2*2H.sub.2O in 50 ml of
distilled water was added thereto and then was further stirred for
three hours. The resulting solution was purified through
centrifugation and then vacuum-dried. As a result, particles
including Cu and In in a ratio as follows: Cu:In of 2.64:3.10 were
obtained. SEM-EDX results of the particles are illustrated in FIG.
9.
EXAMPLE 6
[0124] Synthesis of (In,Ga).sub.2Se.sub.3--CuSe particles
[0125] Under a nitrogen atmosphere, 1.135 g of NaBH.sub.4 was added
to 50 ml of distilled water and dissolved therein. Subsequently, a
solution produced by dissolving 1.935 g of H.sub.2SeO.sub.3 in 30
ml of distilled water was added thereto. After confirming formation
of a colorless and transparent solution, a solution produced by
dissolving 1.548 g of InCl.sub.3 and 1.351 g of GaI.sub.3 in 50 ml
of distilled water was added thereto and then was further stirred
for 1 day, resulting in In.sub.0.7Ga.sub.0.3Se.sub.1.5 particle
formation. Under a nitrogen atmosphere, after dissolving 0.666 g of
NaBH.sub.4 in 50 ml of distilled water in another flask and then a
solution produced by dissolving 1.135 g of H.sub.2SeO.sub.3 in 20
ml of distilled water was added thereto. The resulting mixture was
stirred until a clear solution was observed. To this clear
solution, the previously manufactured (In,Ga).sub.2Se.sub.3
solution was added. Subsequently, a solution produced by dissolving
1.364 g of CuCl.sub.2*2H.sub.2O in 50 ml of distilled water was
added thereto and then was stirred for six hours. The resulting
solution was purified through centrifugation and then vacuum-dried,
resulting in particles having a
Cu.sub.0.81In.sub.0.74Ga.sub.0.26Se.sub.2.5 composition. The
particles were analyzed using ICP. As a result, it was confirmed
that the Cu.sub.0.81In.sub.0.74Ga.sub.0.26Se.sub.2.5 composition
particles have a composition as follows: Cu:In:Ga:Se:Na:B of
17.62:16.18:5.61:56.22:4.16:0.22 in mol %. In addition, as an XRD
analysis result, the particles were observed as having a CuSe
crystalline phase and as being in a mix state of amorphous
(In,Ga).sub.2Se.sub.3 and CuSe having superior crystallinity.
SEM-EDX and XRD results of the particles are illustrated in FIGS.
10 and 11.
EXAMPLE 7
[0126] Synthesis of In.sub.2Se.sub.3--CuSe particles
[0127] Under a nitrogen atmosphere, 1.248 g of NaBH.sub.4 was added
to 50 ml of distilled water and dissolved therein. Subsequently, a
solution produced by dissolving 2.128 g of H.sub.2SeO.sub.3 in 30
ml of distilled water was added thereto. After confirming formation
of a colorless and transparent solution, a solution produced by
dissolving 2.212 g of InCl.sub.3 in 50 ml of distilled water was
added thereto and then was further stirred for 1 day, resulting in
In.sub.2Se.sub.3 particle formation. Under a nitrogen atmosphere,
after dissolving 0.832 g of NaBH.sub.4 in 50 ml of distilled water
in another flask and then a solution produced by dissolving 1.419 g
of H.sub.2SeO.sub.3 in 20 ml of distilled water was added thereto.
The resulting mixture was stirred until a clear solution was
observed. To this clear solution, the previously manufactured
In.sub.2Se.sub.3 solution was added. Subsequently, a solution
produced by dissolving 1.705 g of CuCl.sub.2*2H.sub.2O in 50 ml of
distilled water and a solution produced by dissolving 0.111 g of
polyvinylpyrrolidone in 20 ml of distilled water were added thereto
and then was stirred for five hours. The resulting solution was
purified through centrifugation and then vacuum-dried, resulting in
particles having a CuInSe.sub.2.5 composition. The particles were
analyzed using ICP. As a result, it was confirmed that the
CuInSe.sub.2.5 composition particles have a composition as follows:
Cu:In:Se:Na:B of 19.49:19.97:48.81:3.75:7.98 in mol . In addition,
as an XRD analysis result, the particles were observed as having a
CuSe crystalline phase and as being in a mix state of amorphous
In.sub.2Se.sub.3 and CuSe having superior crystallinity. SEM-EDX
and XRD results of the particles are illustrated in FIGS. 12 and
13.
COMPARATIVE EXAMPLE 1
[0128] 8 mmol of CuCl, 10 mmol of InCl.sub.3 and 20 mmol of Se
powder were added to 100 ml of oleylamine and then were stirred for
four hours while heating to 80.degree. C. under vacuum suction.
Subsequently, the resulting mixture was reacted for four hours at
240.degree. C. under a nitrogen atmosphere and then was cooled off.
The resulting reactant was purified through centrifugation using
hexane and ethanol. As a result, nanoparticles having a
CuInSe.sub.2 composition were obtained. SEM-EDX and XRD results of
the particles are illustrated in FIGS. 14 and 15.
EXAMPLE 8
[0129] Manufacture of Thin Film
[0130] Particles having a CuIn.sub.0.7Ga.sub.0.3Se.sub.2.5
composition manufactured according to Example 4 were added to a mix
solvent including ethanol, ethylene glycol monomethyl ether,
acetylacetone, propylene glycol proyl ether, cyclohexanone,
ethanolamine, 1,2-propanediol, diethylene glycol monoethyl ether,
glycerol and sodium dodecyl sulfate, and then were dispersed in a
concentration of 21% to manufacture an ink. The obtained ink was
coated on glass coated with a Mo thin film and then dried up to
200.degree. C. The coated glass was heat-treated at 550.degree. C.
under a Se-containing atmosphere, resulting in a CIGS thin film.
SEM-EDX and XRD results of the resulting thin film are illustrated
in FIGS. 16 and 17.
EXAMPLE 9
[0131] Manufacture of Thin Film
[0132] The particles having a CuIn.sub.0.7Ga.sub.0.3Se.sub.2.5
composition manufactured according to Example 4 and CuSe particles
were mixed in a ratio of 24% and 1.2%. The resulting mixture was
added to a mix solvent including ethylene glycol monomethyl ether,
propylene glycol proyl ether, ethanolamine, 1,2-propanediol and
diethylene glycol monoethyl ether, and then dispersed to
manufacture an ink. The obtained ink was coated on glass coated
with a Mo thin film and then dried up to 200.degree. C. The coated
glass was heat-treated at 550.degree. C. under a Se-containing
atmosphere, resulting in a CIGS thin film. SEM-EDX and XRD results
of the resulting thin film are illustrated in FIGS. 18 and 19.
EXAMPLE 10
[0133] Manufacture of Thin Film
[0134] The particles having a
Cu.sub.0.8In.sub.0.7G.sub.0.3Se.sub.2.5 composition manufactured
according to Example 6 and Cu.sub.0.87Se nanoparticles were mixed.
The resulting mixture was added to a mix solvent including ethylene
glycol monomethyl ether, propylene glycol proyl ether,
ethanolamine, 1,2-propanediol and diethylene glycol monoethyl
ether, and then dispersed to manufacture an ink. The obtained ink
was coated on glass coated with a Mo thin film and then dried up to
200.degree. C. The coated glass was heat-treated at 550.degree. C.
under a Se-containing atmosphere, resulting in a CIGS thin film.
SEM-EDX and XRD results of the resulting thin film are illustrated
in FIGS. 20 and 21.
EXAMPLE 11
[0135] Manufacture of Thin Film
[0136] Particles having a CuInSe.sub.2.5 composition manufactured
according to Example 7 were added to a mix solvent including
ethanol, ethylene glycol monomethyl ether, acetylacetone, propylene
glycol proyl ether and cyclohexanone, and then were dispersed in a
concentration of 20% to manufacture an ink. The obtained ink was
coated on glass coated with Mo thin film and then dried up to
160.degree. C. The coated glass was pressed with a pressure of 300
bar and then heat-treated at 550.degree. C. under a Se-containing
atmosphere, resulting in a CIS thin film. SEM-EDX and XRD results
of the resulting thin film are illustrated in FIGS. 22 and 23.
COMPARATIVE EXAMPLE 2
[0137] Manufacture of Thin Film
[0138] Particles having a CuInSe.sub.2 composition manufactured
according to Comparative Example 1 were added to a mix solvent
including ethanol, ethylene glycol monomethyl ether, acetylacetone,
propylene glycol proyl ether, cyclohexanone and then dispersed in a
concentration of 20% to manufacture an ink. The obtained ink was
coated on glass coated with a Mo thin film and then dried up to
160.degree. C. Subsequently, the coated class was pressed at a
pressure of 300 bar and then heat-treated at 550.degree. C. under a
Se-containing atmosphere, resulting a CIS thin film. SEM-EDX and
XRD results of the resulting thin film are illustrated in FIGS. 24
and 25. As shown in FIG. 24, it was confirmed that the thin film
manufactured using the CuInSe.sub.2 particles had lots of voids and
particle growth was slow.
EXAMPLE 12
[0139] Manufacture of Solar Cell having Thin Film
[0140] A CdS buffer layer was manufactured on a CIGS thin film
manufactured according to Example 8 using a CBD method.
Subsequently, ZnO and Al:ZnO were sequentially deposited on the
CIGS thin film by sputtering and then an Al electrode was deposited
on the deposited CIGS thin film by e-beam to manufacture a cell.
The resulting cell showed characteristics as follows:
J.sub.sc=24.86 mA/sqcm, V.sub.oc=0.23 V, FF=36.55%, and
Eff=2.09%.
EXAMPLE 13
[0141] Manufacture of Solar Cell having Thin Film
[0142] A CdS buffer layer was manufactured on a CIGS thin film
manufactured according to Example 9 using a CBD method.
Subsequently, ZnO and Al:ZnO were sequentially deposited on the
CIGS thin film by sputtering and then an Al electrode was deposited
on the deposited CIGS thin film by e-beam to manufacture a cell.
The resulting cell showed characteristics as follows:
J.sub.sc=29.33 mA/sqcm, V.sub.oc=0.42 V, FF=42.0% and
Eff=5.20%.
EXAMPLE 14
[0143] Manufacture of Solar Cell having Thin Film
[0144] A CdS buffer layer was manufactured on a CIGS thin film
manufactured according to Example 9 using a CBD method.
Subsequently, ZnO and Al:ZnO were sequentially deposited on the
CIGS thin film by sputtering and then an Ag electrode was deposited
on the deposited CIGS thin film by screen-printing to manufacture a
cell. The resulting cell showed characteristics as follows:
J.sub.sc=34.07 mA/sqcm, V.sub.oc=0.30 V, FF=34.28% and
Eff=3.48%.
EXAMPLE 15
[0145] Manufacture of Solar Cell having Thin Film
[0146] A CdS buffer layer was manufactured on a CIGS thin film
manufactured according to Example 10 using a CBD method.
Subsequently, ZnO and Al:ZnO were sequentially deposited on the
CIGS thin film by sputtering and then an Al electrode was deposited
on the deposited CIGS thin film by e-beam to manufacture a cell.
The resulting cell showed characteristics as follows:
J.sub.sc=26.87 mA/sqcm, V.sub.oc=0.43 V, FF=49.01% and Eff=5.61%. A
graph showing current-voltage characteristics of a solar cell using
the thin film is illustrated in FIG. 26.
EXAMPLE 16
[0147] Manufacture of Solar Cell having Thin Film
[0148] A CdS buffer layer was manufactured on a CIS thin film
manufactured according to
[0149] Example 11 using a CBD method. Subsequently, ZnO and Al:ZnO
were sequentially deposited on the CIS thin film by sputtering and
then an Al electrode was deposited on the deposited CIS thin film
by e-beam to manufacture a cell. The resulting cell showed
characteristics as follows: J.sub.sc=28.37 mA/sqcm, V.sub.oc=0.23
V, FF=34.08% and Eff=2.19%.
COMPARATIVE EXAMPLE 3
[0150] Manufacture of Solar Cell having Thin Film
[0151] A CdS buffer layer was manufactured on a CIS thin film
manufactured according to Comparative Example 2 using a CBD method.
Subsequently, ZnO and Al:ZnO were sequentially deposited on the CIS
thin film by sputtering and then an Al electrode was deposited on
the deposited CIS thin film by e-beam to manufacture a cell. The
resulting cell showed characteristics as follows: J.sub.sc=13.45
mA/sqcm, V.sub.oc=0.18 V, FF=26.63% and Eff=0.6%.
EXPERIMENTAL EXAMPLE 1
[0152] Compositions of particles manufactured according to Examples
1 to 7 and Comparative Example 1 were analyzed. Results are
summarized in Table 1 below. Photoelectric efficiencies of thin
film solar cells, which are based on the above particles,
manufactured according to Examples 12 to 16, and Comparative
Example 3 were measured. Results are summarized in Table 2
below.
TABLE-US-00001 TABLE 1 Cu Se or S In Ga atomic % atomic % atomic %
atomic % Example 1 23.9 52.85 23.26 -- Example 2 24.86 55.21 19.94
-- Example 3 27.17 51.9 20.93 -- Example 4 25.67 51.77 13.86 8.7
Example 5 28.48 49.86 21.66 -- Example 6 22.45 57.05 13.22 7.29
Example 7 25.08 47.63 27.28 -- Comparative 24.83 51.82 23.35
Example 1
TABLE-US-00002 TABLE 2 J.sub.sc V.sub.oc FF Photoelectric
(mA/cm.sup.2) (V) (%) efficiency (%) Example 12 24.86 0.23 36.55
2.09 Example 13 29.33 0.42 42.0 5.20 Example 14 34.07 0.30 34.28
3.48 Example 15 26.87 0.43 49.01 5.61 Example 16 28.37 0.23 34.08
2.19 Comparative 13.45 0.18 26.63 0.6 Example 3
[0153] In Table 2, J.sub.sc, which is a variable determining the
efficiency of each solar cell, represents current density, V.sub.oc
denotes an open circuit voltage measured at zero output current,
the photoelectric efficiency means a rate of cell output according
to irradiance of light incident upon a solar cell plate, and fill
factor (FF) represents a value obtained by dividing a value
obtained by multiplication of current density and voltage values at
a maximum power point by a value obtained by multiplication of Voc
by J.sub.sc.
[0154] Referring to Table 2 and FIG. 26, the CI(G)S thin films
manufactured using the aggregated precursor according to the
present invention showed improvement in the current intensity, open
circuit voltage, and photoelectric efficiency, when compared to
CI(G)S thin films manufactured by using single-phase particles of
the prior CuInS(Se).sub.2. Especially, the current intensity and
open circuit voltage of the CI(G)S thin films manufactured using
the aggregated precursor according to the present invention were
extremely superior.
[0155] Those skilled in the art will appreciate that various
modifications, additions and substitutions are possible, without
departing from the scope and spirit of the invention as disclosed
in the accompanying claims.
INDUSTRIAL APPLICABILITY
[0156] As described above, when a thin film is manufactured using
an aggregated precursor including a first phase including a copper
(Cu)-containing chalcogenide and a second phase including an indium
(In) and/or gallium (Ga)-containing chalcogenide according to the
present invention manufactured in one reactor through a sequential
process, the thin film has an entirely uniform composition and is
stable against oxidization. In addition, the precursor includes S
or Se and thereby the amount of a Group VI element in a final thin
film is increased, and, accordingly, a superior quality thin film
may be manufactured.
* * * * *